Questions tagged [weather]
Weather means the atmospheric conditions, including wind, temperature and precipitation, in a specific area at a specific time.
316
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1answer
956 views
What is the red barb for in the NOAA weather briefing?
Wind barbs are well-defined symbols, but I noticed in my WX briefing that there are now occasional red barbs in the chart.
The red appears on both the 5kt and 10kt barbs, and sometimes for largest ...
10
votes
3answers
1k views
Can gusts be reported as lower than wind speed?
KADS 072350Z 31030G20KT 13SM SKC 24/02 A2980
I’ve never seen a negative gust factor before. Is that a real thing (and if so, what does it mean), or did someone just make a typo?
2
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1answer
103 views
When was the last time the US Standard Atmosphere 1976 was updated?
I imagine due to slight changes in Earth's atmosphere or more accurate instrumentation it's been updated at least once, but also because it's understood to be a less precise model we might not have ...
1
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1answer
88 views
How to get an accurate time of arrival to the en-route alternate airport during flight planning?
I was thinking about accurate criteria of selecting en-route alternate (ERA) weather from ground (planning stage) especially for ERA 3% contingency flight plan.
As we all know we should care about one ...
3
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2answers
1k views
Can I derive the wind speed and direction? [duplicate]
If I know the IAS and GS (with directional components) of an aircraft, can I derive the wind speed and direction?
I'm working on an application that simulates the flight of an aircraft. Another ...
0
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1answer
69 views
What are the Requirements for the implimentation of Low Visibility Procedures at an airport?
So I was wondering if the RVR at an airport is reported above CAT I conditions for eg 1400 Meters etc but the Visibility is 50 to 100 Meters then would the pilots carry out non instrument approach or ...
4
votes
1answer
139 views
Why are the airport pressure values for “altitude” (inHg) and “sea level” (mb) slightly different on the NOAA web sites?
If one looks, for example, at the NOAA web site for Denver International Airport we see (at the time of posting this question) the Pressure/Altimeter is 29.78 inHg, the Pressure/sea level is 1006.1 mb ...
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0answers
55 views
A scenario question regarding meteorology
In the image attached, I’m struggling to find out why the answer is the way it is; maybe is me not being able to visualise it, but some help would be greatly appreciated.
2
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1answer
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What causes Gusty winds? ( Meteorlogy) [closed]
I was wondering why winds can become gusty. I know that gusty winds tend to be related with frontal passage. Thanks : )
2
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3answers
115 views
What weather should we expect when temperature and dew point are similar?
What should i expect during my flight planning when i see both temperature and dew point are the same?
I understand there will be fog but what else? could it mean icing? any difference between 20/20 ...
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1answer
82 views
Why is cloud base estimation taught in Fahrenheit?
I've seen the formula for estimating cloud base consistently presented using Fahrenheit temperature and dewpoint (for example, see PHAK 12-14; Jeppesen also teaches it this way):
$$
\mathrm{cloud\:...
0
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1answer
92 views
How can I calculate ambient air pressure from flight data?
I am playing around with data collected during a flight. I would like to find out the (real, not ISA) ambient air pressure for each data point, since it is not reported in the spread sheet containing ...
2
votes
1answer
98 views
How can air stability be predicted?
After several weeks of being grounded due to low clouds, I was looking forward to the cool air, clear skies, high pressure and light winds that arrived this morning as forecasted. However, there is an ...
0
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1answer
82 views
What is the difference between the WSUSnn IDs used in convective SIGMETs?
When NOAA issues a convective SIGMET, it falls under one of three bulletin IDs: WSUS31, WSUS32, or WSUS33. Below are three examples from the current forecast.
WSUS31:
...
1
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1answer
285 views
What is the difference between mist and haze in terms of relative humidity?
I am an aviation meteorologist and I struggle to distinguish the two of them.
0
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1answer
319 views
Where can I listen online to live VOLMET broadcasts?
Are there sites that stream live VOLMET broadcasts? I need to listen to the format but haven't have the time to put together an amateur radio.
37
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2answers
7k views
What do pilots landing on aircraft carriers do when the ship is not visible due to weather?
Say an aircraft takes off of a carrier to do a mission somewhere, and upon returning to the carrier the pilot comes to find that a thick layer of fog has formed just above the surface of the water in ...
0
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2answers
143 views
Does DA/DH refers to ceiling?
If airport is reporting FEW001 or SCT001 and RVR is above 600m, does it means that there will be no LVO because ceiling is defined as more than 4/8 and DA/DH will be more than 100ft because DA/DH is ...
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1answer
56 views
Are AWOS data open for commercial use? [closed]
I 've found out this great website where you can get historical AWOS weather data. I would like to use it for a commercial application but I don't find any data license. Do you know if the AWOS data ...
1
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1answer
73 views
Where is there an FAA source that states that squall lines are non-frontal?
There's a question in the FAA commercial question bank that indicates that squall lines are nonfrontal, and the reference for the question points to the Aviation Weather Advisory Circular.
The word, &...
9
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4answers
710 views
Can the “G” and “VRB” wind conditions be combined in METARs?
I have never seen the "VRB" (for wind direction variations < 60°; e.g. VRB12003KT) and "G" annotation (for gusts > 10KT wind speed difference; e.g. 12003GT30KT) being combined in a METAR.
Until ...
1
vote
1answer
60 views
How would a pilot apply the information found on a 500 Millibar Vorticity chart to a flight?
The U.S. Flight Service website has these weather products listed:
I have circled the 500 Millibar Vorticity Charts. I've been a pilot for 10+ years and have never heard mention of this chart by ...
3
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2answers
131 views
Is AMDAR a required system on aircraft?
I was intrigued by the assertion that COVID-19 depressing commercial aviation has lead to lower quality weather forecasting
The aircraft observations are a key piece in the jigsaw of national and ...
5
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1answer
146 views
Does a METAR report variable wind direction in a clockwise direction?
Does the convention for reporting variable wind direction always use a clockwise (nautical) sense?
For example, if the wind varies between 340 degrees and 10 degrees, assuming a clockwise sense the ...
2
votes
1answer
87 views
Is an area of localized reduced visibility considered to be a cloud?
If there an area containing visible moisture in an otherwise clear sky and that area of visible moisture is transparent is it considered a "thin cloud" or simply a "localized area of reduced ...
2
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1answer
142 views
What is an approved weather source for flying an instrument approach into an airport with no working ATIS?
What can you use as viable weather information landing at an airport with ATIS inoperative due to the tower being closed after hours? Let's assume the approach secondary weather source is also ...
12
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2answers
2k views
Who makes the call to start in terrible weather conditions?
I once headed to the airport during a huge thunderstorm with winds above 55 knots and massive rain and some small hail. At the airport, I saw that most flights were delayed or even canceled. To my ...
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2answers
323 views
Are helicopters impacted by fog more than airplanes?
With the crash of Kobe Bryant's helicopter, it seems a lot of focus has been placed on the helicopter flying low in fog (under "special VFR"). However, I've seen several suggestions that the ...
4
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0answers
252 views
How far can the sound of a sonic boom travel? [closed]
Are there conditions or distances from the plane to cloud to the observer in which a sonic boom from a plane is muted?
0
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2answers
102 views
Why and how do atmospheric properties sometimes vary from the ISA? [closed]
I'm curious as to why sometimes atmospheric properties don't match the ISA's. One reason I am considering is due to calibration discrepancies. By atmospheric properties I mean temperature, Density, ...
14
votes
5answers
7k views
Why did my LGA-ORD flight make an S-shaped turn round the time it was passing a storm?
On a recent United UA1709 flight into Chicago (hit by a heavy storm at the time), I felt a noticeable descent, combined with two wide banks around 1 hour before landing. Looking at the flight path, I ...
10
votes
1answer
2k views
How do pilots avoid thunderstorms at night over the pacific en route to Australia where there is no radar? And what if a large front develops?
While there is some limited radar on board for pilots, we hear that there is no radar over the ocean which is why flight locations are estimated. As the distance between the United States and ...
4
votes
1answer
412 views
What to do if trapped on top VFR?
In the event that, despite his best efforts, a VFR-only pilot has gotten trapped on top of a solid cloud layer, what is(are) the safest course(s) of action?
For example, consider a long cross-country ...
2
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1answer
164 views
How to avoid getting trapped on top VFR?
This question addresses whether it is legal to fly VFR over-the-top.
One of the comments mentioned the difference between safety and legality, i.e. doing so may not be safe even if it is legal (in ...
4
votes
1answer
8k views
What fomula use for calculating pressure altitude?
I'm having some trouble making my calculations of pressure altitude match those in apps and text books.
I'm using the formula from Wikipedia:
(29.92 - altimeter setting) * 1000 + airport elevation ...
2
votes
1answer
782 views
What is the difference between ACARS and ADS-B?
What is the difference between ACARS and ADS-B?
For weather information in-flight or pre-flight which one is used?
7
votes
1answer
2k views
Does the coriolis force have an effect on the direction in which an aircraft travels?
Suppose an aircraft is flying from Kenya (which lies on the equator) to UK (which lies in the northern hemisphere). Does the Coriolis force veer the aircraft to the right? Do pilots have to correct ...
1
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1answer
615 views
Can you continue an ILS approach when weather falls below minimum?
If, after passing the final approach fix, weather deteriorates so that the reported values are now below required minima, is it allowed to continue the approach?
1
vote
1answer
145 views
What is the reasoning behind this question about the correct altitude to avoid clear icing?
This question has been killing me for a while and it's an original PPL question:
You are approaching to an airmass with a temperature of 6 C at
10000ft. Which altitude should you be in order to avoid ...
1
vote
1answer
232 views
Why jet stream is stronger in winter?
I notice in a website taling about jetstream
https://www.weather.gov/jetstream/jet
It says:
The winds blow from west to east in jet streams but the flow often shifts
to the north and south. ...
0
votes
4answers
125 views
Can airflow reverse over the flight surfaces of a uav in high wind conditions
Can airflow reverse over the wing of a uav in high tail winds and low forward airspeed i.e 25knt fwd airspeed in a 35 knt tailwind? What would be the overall effect on the elevator and rudder? I ...
3
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2answers
1k views
Approach when weather condition is below minimum
If airport weather condition is below minimum, but pilot report that flight weather condition is above minimum, Does controller can issue approach clearance to pilot?
If weather condition get worse ...
6
votes
3answers
174 views
NEXRAD—why is it 2D?
If you paid attention to NEXRAD training, you know that the colors of pixels show the maximum activity at any altitude in that air column. (It’s a “composite” view.)
NEXRAD itself samples in three ...
22
votes
3answers
6k views
How did pilots avoid thunderstorms and related weather before “reliable” airborne weather radar was introduced on airliners?
How did airline and or mail pilots avoid hazardous weather especially at night before airborne weather radar systems were in use?
3
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1answer
227 views
Does an uncovered naval aircraft suffer any weathering affects?
This question is for WW2-era naval aircraft.
I noticed that some cruisers and battleships carried a couple seaplanes, launched by catapult and recovered with cranes.
Obviously these are unprotected ...
4
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2answers
4k views
What does NSC mean in a METAR?
Here's a METAR:
SCEL 090000Z 15005KT 5000 HZ NSC 10/08 Q1020 NOSIG
What does NSC mean?
18
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3answers
3k views
When do flights get cancelled due to fog?
When flights get cancelled due to fog, what triggers the cancellation? Fog is too thick, too wide-spread, blocks the view of tall buildings or other landmarks? Or is the problem the type of air ...
5
votes
1answer
127 views
What kind of input is used by NASA's TASAR?
I've found the Aviation SE to be a really interesting read so far, I'm excited to be here! I'm fairly new, but I'm also old!
What are the inputs for TASAR to crunch flight path optimization? Is it ...
0
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1answer
74 views
What the weather condition can affect for flight? [closed]
What is the most disturbing weather conditions for flight?
On another word: what more dangerous for takeoff/landing: wind, precipitation or something else?
0
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3answers
187 views
What does the future of the weather radars look like?
Planes had weather radars for a long time (Dassault Falcon and Learjet35A) which was useful since you either had to ask ATC, listen the ATIS frequency or ask the flight advisory before flight planning ...
